Method of firing and quenching control of gas-discharge tubes



Nov. 14, 1967 L. N. KORABLEV 3,353,063

METHOD OF FIRING AND QUENCHING CONTROL OF GAS-DISCHARGE TUBES Filed Oct. 26, 1964 United States Patent Ofifice 3,353,063 Patented Nov. 14, 1967 The present invention relates to a method of firing and quenching gas-discharge cold-cathode tubes.

I am aware that prior to my invention various methods of firing and quenching gas-discharge cold-cathode tubes were known and that, in respect to such tubes, one of the main disadvantage is their poor sensitivity.

It is also known that the utilization of gas-discharge tubes in combination with semiconductor devices, e.g. for the indication of semiconductor-device operation in computing machines, proves to be uneconomical and that it is necessary to use either auxiliary amplifying stages comprising costly high-voltage transistors or electron-ray indicator tubes with hot cathodes and phosphor plate.

Though many attempts were made to overcome the above mentioned disadvantages, none of them have given positive results for commercial realization. For example, gas-discharge tubes were filled with radioactive substances which diminish their firing time, but radioactive decay resulted in considerable scattering of their characteristics.

It is an object of the present invention to provide a method for improving the sensitivity of gas-discharge coldcathode tubes.

It is another object of the present invention to stabilize the threshold parameters of gas-discharge cold-cathode tubes.

In accordance with said objects of the present invention, there is proposed a method of control 'over the firing of gas-discharge cold-cathode tubes which consists in that:

The electrodes of the tubes are supplied with an auxiliary pulse voltage from an external supply source in addition to the main controlling voltage.

Other objects and advantages of the present invention will become obvious from the following description and the accompanying drawings, in which:

FIG. 1 shows the circuit to perform a proposed method comprising a double-electrode gas-discharge cold-cathode tube, the firing pulse voltage being supplied from an external source to one of the tube electrodes; and

FIG. 2 shows a circuit to perform the proposed method comprising a multi-electrode gas-discharge cold-cathode tube with a cold cathode in which the firing pulse voltage is generated in the grid circuit of the tube.

The proposed method for the control of firing and quenching control of gas-discharge tubes with cold-cathodes consists in that the tube electrodes are supplied with a pulse voltage having a suitable magnitude together with the main control voltage. To diminish the amplitudes of the control signals, the slow discharge or sustaining voltage is taken as the main threshold parameter determining the sensitivity of the tube and the firing voltage becomes an auxiliary parameter of the tube. The gas-discharge coldcathode tube is supplied with a voltage almost equal to the discharge voltage of the tube. The loading resistance is chosen to be small enough to provide the necessary operating current passing through the gas-discharge tube for glow discharge. During the operation of the gas-discharge tube in case a small negative signal is fed to it, the voltage between the electrodes becomes less than the discharge voltage and the discharge stops. When the negative signal ceases or a positive signal is supplied to the tube, the voltage across is becomes higher than the discharge voltage and due to the auxiliary firing voltage gitl the necessary magnitude the gas-discharge tube is In a gas-discharge cold-cathode tube with an increased sensitivity these appears a continuous discharge when the master voltage is greater than the discharge voltage.

The amplitude oscillations of the pulses do not influence the circuit operation.

The firing conditions of a gas-discharge cold-cathode tube are determined by the formula The quenching conditions for the negative input signals are calculated as follows U u U preserving the following conditions for the positive input signals The tube goes out when U =0, where U is a voltage of the supply source; U is an input signal voltage;

U is a firing pulse voltage;

U is a glow discharge voltage;

U is a firing voltage.

In case multi-electrode gas-discharge tubes are used, the pulse voltage generated in the grid circuit of said tubes may be used instead of a firing pulse voltage from an external supply source. A relaxation autogenerator of voltage firing pulses can be formed in the grid-cathode circuit of the tube. When the tube has been operated from an input signal, the relaxation oscillations stop automatically. This property of the gas-discharge tube allows to utilize it as a controlled generator whose operation is controlled by small direct-current signals.

The firing and quenching of gas-discharge tubes in accordance with the proposed method have been effected with a pulse voltage having the amplitude of 0.1-0.2 volt.

The control of the firing and quenching of gas-discharge tubes in accordance with the proposed method for a double-electrode gas-discharge tube is exemplified by the circuit presented in FIG. 1 where a gas-discharge tube 1 is supplied from a power supply source 2. The current flowing in the circuit of the supply source as regards the voltage value is close to the glow discharge voltage. From the source 3 of input signals the input signals are fed to the gas-discharge tube circuit comprising load 4 such as a transformer, a resistor, or the like. The supply source 5 of the firing pulse voltage feeds the tube 1 with the firing pulse voltage of the required pulse magnitude and ratio and at definite time intervals the voltage at the tube 1 equals or exceeds the discharge voltage value.

The control of operation of the tube 1 is performed by an input signal, which diminishes the applied voltage to a value lower than the discharge voltage when the tube 1 is supplied with a negative input signal or when the value of the input signal is equal to zero.

If it is necessary to generate these pulses in the grid circuit of a multi-electrode tube instead of using a separate generator or an external firing pulse supply sourcev The present invention relating to methods of the firing and quenching of-gas-discharge tubes is described in connection with preferred embodiments.

It is evident that alterations and modifications may be made in the invention as disclosed herein without departing from the spirit and scope thereof as those skilled in the art willeasily understand.

What is claimed is:

1. A circuit comprising a cold-cathode gas-discharge tube having characteristic sustaining and firing voltages, means for applying to said tube a direct-current bias voltage substantially equal to said sustaining voltage, means to apply auxiliary periodic unidirectional pulses of predetermined duration to said tube which in combination with said direct-current bias voltage provide a cumulative voltage waveform ofa magnitude which periodically varies between levels greater than the sustaining voltage but less than said firing voltage, and means to apply positive and negative control pulses of predetermined durationselectively to said tube, the duration of each control pulse being greater than the duration of each auxiliary pulse, said positive pulses in combination with said cumulative voltage enabling a triggering of said tube, said negative pulses in combination with said direct current voltage efiecting an extinguishing of said-tube.

2. A circuit as claimed in claim 1 wherein themeans to apply the auxiliary pulses is an external pulse source.

3. A circuit as claimed in claim 1 wherein the means to apply the auxiliary pulses comprises a relaxation oscillator connected to said tube and means for applying a direct-current voltage; said tube including a grid-coupled to said relaxation oscillator and a separate electrode to which the direct-current voltage is applied.

References Cited UNITED STATES PATENTS 2,797,368 6/;1957 Holden Sly-3 3 5 X 2,920,239 1/1960 Saeger 315 170 JAMES D. KALLAM, Primary Examiner.

JOHN W. HUCKERT, Examiner.

D. O. KRAFT, R. F. POLLISSAACK,

Assistant, Examiners 

1. A CIRCUIT COMPRISING A COLD-CATHODE GAS-DISCHARGE TUBE HAVING CHARACTERISTIC SUSTAINING AND FIRING VOLTAGES, MEANS FOR APPLYING TO SAID TUBE A DIRECT-CURRENT BIAS VOLTAGE SUBSTANTIALLY EQUAL TO SAID SUSTAINING VOLTAGES, MEANS TO APPLY AUXILIARY PERIODIC UNIDIRECTIONAL PULSES OF PREDETERMINED DURATION TO SAID TUBE WHICH IN COMBINATION WITH SAID DIRECT-CURRENT BIAS VOLTAGE PROVIDE A CUMULATIVE VOLTAGE WAVEFORM OF A MAGNITUDE WHICH PERIODICALLY VARIES BETWEEN LEVELS GREATER THAN THE SUSTAINING VOLTAGE BUT LESS THAN SAID FIRING VOLTAGE, AND MEANS TO APPLY POSITIVE AND NEGATIVE CONTROL PULSES OF PREDETERMINED DURATION SELECTIVELY TO SAID TUBE, THE DURATION OF EACH CONTROL PULSE BEING GREATER THAN THE DURATION OF EACH AUXILIARY PULSE, SAID POSITIVE PULSES IN COMBINATION WITH SAID CUMU- 